Discrepancy in Rendering from original model
I would guess (can't tell for definite without a blend file) that you have a Subsurf Modifier set to be off in the 3D view but on for rendering.

Go to the modifiers panel by clicking the blue spanner/wrench and then see if you have any modifiers.

If the modifier is set to be off in the 3D view then the 'eye' icon will be disabled. Disable the 'Show in render' button (camera icon) to disable the modifier or press the 'x' button to remove it.